Incorporated herein, by reference, in their entirety are U.S. Pat. No. 4,520,113, issued May 28, 1985 to Gallo et al and the article Di Marzo Veronese et al, "Monoclonal Antibodies Specific for P24, the Major Core Protein of Human T-Cell Leukemia Virus Type III," Proc. Natl. Acad. Sci. USA, Volume 82, to be published August 1, 1985; Popovic et al, "Detection, Isolation, and Continuous Production of Cytopathic Retroviruses (HTLV-III) from Patients with AIDS and Pre-AIDS," Science, May 4, 1984, 224:497-500; Gallo et al, "Frequent Detection and Isolation of Cytopathic Retroviruses (HTLV-III) from Patients with AIDS and at Risk for AIDS," Science, May 4, 1984, 224:500-503; Schupbach et al, "Serological Analysis of a Subgroup of Human T-Lymphotropic Retroviruses (HTLV-III) Associated with AIDS," Science, May 4, 1984, 224:503-505; Sarngadharan et al, "Antibodies Reactive with Human T-Lymphotropic Retroviruses (HTLV-III) in the Serum of Patients with AIDS," Science, May 4, 1984, 224:506-508; Schupbach et al, "Antigens on HTLV-Infected Cells Recognized by Leukemia and AIDS Sera are Related to HTLV Viral Glycoprotein," Science, May 11, 1984, 224:607-609; Ratner et al, "Complete Nucleotide Sequence of the AIDS Virus, HTLV-III," Nature, Jan. 24, 1985, 313:227-284; and Safai et al, "Sero Epidemiological Studies of Human T-Lymphotropic Retrovirus Type III, in Acquired Immuno Deficiency Syndrome," The Lancet, June 30, 1984 pp. 1438-1440. These incorporated references, and the references in the copending application cited herein, provide a full description of the background of this invention, the problems that are presently solved, and the uses for the presently claimed cell lines and monoclonal antibodies. They are also incorporated to define the terms and describe the methods and procedures used in the present invention.
The human T-cell leukemia viruses are a family of T lymphotropic retroviruses etiologically associated with the alteration of T cell functions, leading to abnormal proliferation (leukemia) or depletion (immunosuppression) of T lymphocytes. The previous most common isolate, which was also the first isolate, HTLV-I, was obtained from an American patient with an aggressive form of mature T-cell lymphoma (23' and reviewed in 24'). The second isolate, HTLV-II, was first isolated from a patient with a T-cell variant of hairy cell leukemia (25' and reviewed in 24'). HTLV-III has been frequently detected and isolated from patients with acquired immunodeficiency syndrome (AIDS) or with signs and symptoms that frequently precede AIDS (AIDS-related conditions [ARC]) (1'). Isolates closely related or identical to HTLV-III have been obtained by investigators in other laboratories (2',3',26'). AIDS is a newly described disease characterized by severe immune depression with depletion of the OKT4+ subset of T lymphocytes (27',28') and is accompanied by multiple opportunistic infections or neoplasias (26'). Common biological features of all members of the HTLV family include their preferred tropism for T cells (1',30',31'), and morphologic appearance of budding and early forms of the virus under electron microscopy.
Even though HTLV-III is antigenically distinct from HTLV-I and -II, it shares a number of determinants (32',33') and some nucleotide sequence homology (34',35'). Like the other two isolates, HTLV-III has a major structural protein with a molecular weight of about 24,000 (p24) (33'), and a reverse transcriptase with a molecular weight of 100,000, but the protein homologous to p19 is somewhat smaller, having a molecular weight of about 17,000 (p17) (7', and our unpublished data). Another difference involves the in vitro transmission of the virus to primary human T-cells. Whereas HTLV-I and-II can transform some of these cells and be propagated indefinitely in them (30',31'), HTLV-III is only transiently produced in these cells (1'). The problem has been overcome by propagating the virus in a human neoplastic cell line (HT) (1').
Isolation of the AIDS agent has enormous clinical implications because it allows the possibility of developing specific assays to identify HTLV-III infection, the first step in interrupting its spread. The correlation between the presence of antibodies to HTLV-III proteins and AIDS has identified this virus as the causative agent for AIDS (7',8',16'). However, the only reported antibody reagent for subtyping HTLV-III before the present invention is a polyclonal antibody to p24 (33'), which reacts with several different lysate fragments and also exhibits low level cross-reactivity to HTLV-I and -II.
Human T-cell leukemia virus type-III (HTLV-III) has been isolated from several patients with acquired immune deficiency syndrome (AIDS), AIDS-related complex (ARC) and from asymptomatic carriers of infection (1'). Other retroviral isolates from similar sources known as lymphadenopathy associated virus (LAV) (2') and by other names (3') appear to be closely similar to various isolates of HTLV-III, as evidenced by the nucleotide sequences of the respective proviral DNAs (4',5') and endonuclease restriction maps (6'). Epidemiological data on prevalence of antibodies to HTLV-III among various AIDS-risk groups (7',8') and recovery of HTLV-III at high frequency from the same risk groups (1') indicate that HTLV-III is the etiological agent of AIDS. This is further strengthened by the development of AIDS in individuals not belonging to any known risk groups solely as a consequence of blood transfusion (9'); by the observed tropism of the virus for OKT4+ lymphocytes in vitro, and by the profound cytopathic effect of the virus on the OKT4+ lymhocytes both in vitro and in vivo (10'); and by the frequent and reproducible isolation of the virus from semen, saliva and blood of patients with AIDS, ARC and those at risk for these conditions (1',11').